Telephone system.



` H. P. vCLAUSEIL TELEPHONE SYSTEM.

APPLICATION FILED JUNE 4, 1908.

937,050. A Patented ot.19,19o9.

f .ATTORNEY of which the following is -6 has an armature 15,

UNITED sTATEs PATENT oEEioE.

HENRY. P. CLAUSEN, OF CHICAGO,

ILLINOIS,` ASSIGNOR T0 AMERICAN ELECTRIC TELE- PHONE COMPANY, OFCHICAGO, ILLINOIS` A CORPORATION 0F NEW JERSEY.

TELEPHONE SYSTEM.

` Specification of Letters Patent.

`Patented Oct. 19, 1909.

Application filed June I151968. Serial No. 436,546.

To all whom t may concern:

Be it known that I, HENRY P. CLAUSEN, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Telephone Systems,

a full, clear, concise, and exact descriptiomreference being had to t-heaccompanying drawings, forming a part of this specification.

. My inventionv relates to ytelephone systems,`

and has for lit/s object the provision of a new and novel *centralrenergy switchboard circuit, features of the invention being moreparticularly in the nature of: test circuitsfor such central energysystems, in connection with instrumentalities necessary for theadaptation of such test circuits to theg-eneral' central energyswitchboard circuits.

I will describe my invention more in deL tail by reference to theaccompanying drawing, illustrating diagrammatically the' circuitarrangements.

A subscribers station,y comprising a lreceiver, l, transmitter, 2, inconnection With the signaling ringer, 3, are shown as connected by meansof lineA Wires, 4 and 5, to a central -st-ation. rlhe subscriberscircuits are'shown in duplicate more clearly to reveal theinterconnections. Each subscriberls substation circuit is united to thesame line instrumentalities at the central station. Thisis true for thenormal subscribers lines. This Vcentral station vequipment associatedWitheach normal subscribers line, consists of a line relay 6, one of itsterminals being connected to a battery 7 which battery has its positiveterminal grounded.v An 'additional instrumentality for each subscribersline circuit is the cut-olf relay 8, which is provided with an armature9, and having a back-contact, 10. The armature 9 is like- Wise providedwith a front contact 11. -A further armature 12 is under the influenceor control of relay 8, having a back-contact 13', and a front contact,14. The line relay tact .16. A lamp 17 is controlled by the armature15., and front contact 16.. An an- ,swering jack, having a tip-spring18,-and a- 'sleeve spring 19, and a thimble 20, is shown in connectionwith each' subscribers line circuit, and the same answering'jack springsand thimble are multiplied through to various multiple jacks, as shown.When the disconnects the 'lin-e relay which has a front .Con'

subscriber removes his receiver from the switch-hook, a closed circuit1s ellected at the sub-station of the line Wires Ll and A current nowpasses from the negative ter.

minal of the battery 7 to the line relay 6, back-contact 10, armature 9line conductors 4 and 5, through the substation set, through thearmature 12, through back-contact 13, to ground, which is connected tosaid positive batteryterminal 7, thus pulling up relay 6, whichenergizes the lamp 17, and gives the line signal. The answering plug,co1npris ing a tlp contact 21, and a sleeve contact 22, is then insertedint-o the jack, and this immediately causes .anenergizing of the cut-ottrelay 8, byl reason of the fact that current. from the negative terminalof the battery 7 flows through the supervisory relay 23.v

through the sleeve contact ofthe answering plug, through the thiinble20, thence through the cut-of relay 8, back to the positive terminal ofthe battery, as here shown, through the ground connection. Thisimmediately 6, and causes the lamp 17 to be extinguished.

It will thus be seen that negative battery7 is connected to thimble 20of a talking sub scribers line. The reason for this will be *A more-apparent hereafter when it is explained that 1n order to geta-busy'test, it is necessary for the calling plug to come in contactwith negative battery at the thimble. A

calling plug having a tip contact 24, and a sleeve contact 25, isassociated in the same cord circuit With the answering plug havingcontacts 21 and 22 respectively. A ringing key connected to,..agenerator 26, as Well understood, is shown. The cord circuit between theanswering and calling plug is broken by condensers 27, 27, so far asdirect currents are concerned, hoWever,'these condensers offerpractically no opposition to the talking current. p

A listening key, having springs 28, 2S), connected to the'answeringplug, is shown, and this key, by means of springs 30, 30 effects'connection with the -operators talking set, comprising the headreceiver, .31', transmitter, 32, primary of the induction coil, 33,secondary' of-induction coil, 34, and condenser, 35. Theprimary 33 ofthe induction coil,y and the transmitter' 32', must be connected to somesuitablelsource of current, not here shown. The ringing spring 29 isfurthervsecured yan insulating bushing to a spring'36, having a backcontact 37, toA be used for busy test purposes, as will be more clearlyset, forth hereinafter.

' Battery current from the negative pole of the battery 7 is furnishedto theA line con# ductorl 4', through the sleeve spring 19, the

sleeve of theplug 22, and the supervisoryl relay 23. Positive batterycurrent is furnished from the positive pole of the battery, through thesupervisory relay 38,.-to the tip .current conductor, from there throughthe positive battery current to line conductors when the calling plug isinserted in the jack.

I have previously stated that when any subscriber is busy, the thimbles20 are con nected to negative battery. It will thus be4 seen that shouldthe calling plug ti 24 come in contact, for instance, witht imble 20,which is connecteduwith negative battery, a circuit Will be establishedfrom said thimble 20, through tip 24, through the ringing key springs,through the relay 42, the armature 43, through the wire 44, the backcontact spring 37, the spring 36, tertiary coil 45 and impedance coil 46to ground. or storage battery. A flow of current will therefore takeplace between the positive and negative terminals Vof the battery 7,through my new and novel coil 45.

The coil 45' is in inductive relation with the coils 34 and 33, so thatthe Vflow of cul'- rent in said coil 45 will cause a click 'in theoperators receiver 31, apprising the operator that the called-for lineis busy. The great advantages of arranging the busy test circuit in thisway are due to the dampening eiiect of the click as secured by theinterposition of the impedance coil 46, and the Winding of the relay 42,which winding thus serves a double purpose. Itis, of course, understoodthat in making the busy test, the listening key, comprising the springs28 and 29, is to bel actuated outwardly to effect the connectionsnecessary.

Having thus described my improved circuit, what I claim as new, anddesire to secure by Letters Patent is:

1. A telephone system, comprising line circuits and a cord circuit, asupervisory relay in said cord circuit, an operators talking circuit insaid lcord circuit, and means for establishing a busy test circuitthrough said operators talking circuit, and said supervisory relay.

2. A telephone system, comprising line circuits and a cord circuit, asupervisory relay insaid cord circuit, an operators talking circuit,having an induction coil provided With a tertiary winding, and means forestablishing a busy test circuit through said relay and said tertiarywinding. In witness whereof, I hereunto subscribe `my name this secondday of June A. D., 1908.

HENRY P. CLAUSEN.-

Witnesses:

E. B. CAMPBELL, O. M. NENNIcL.

